Telephone-exchange system



Dec, 2, 1924.

F. A. STEARN TELEPHONE EXCHANGE sYsTEM Filed Dec. '30. i921 6 Sheets-Sheet 1 Ffa/m27 A. s/W/z ec. 2.,; l 92% F. A. STEARN TELEPHONE EXCHANGE SYSTEM 'Filed Dec. so,

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F. A, STEARN TELEPHONE EXCHANGE SYSTEM Filed Dec. 50

@n Num Sm 1,517,260 F. A. STEARN TELEPHONE EXCHANGE SYSTEM Filed Dec. :5o. 1921 e Sheng-sheet 4 /m/enfaf.'

F. A. STEARN TELEPHNE EXCHANGE SYSTEM e sheets-sheets Mam/0f' Fra/7h07 .SIM/W.

Filed Dec. 30. i921 50 1921 6 Sheets-Sheet 6 F. A. STEARN TELEPHONE EXCHANGE SYS TEM Filed Dec.

Dec. 2, 1924.

Patented Dec. 2, i924.

FRANKLIN ANDREW STEARN, 0F PATERSON, NEVI JERSEY, ASSG-NOR TO NESTERN ELECTRIC COMPANY, INCORPORATED, OTE NEW "YORK, kN. Y., A CORPORATION OF NEW YORK.

Application led December 30, 1921,

To all fui/20mA t may core/cera:

Be it known that L'FRANKLIN finnnnw Streams, a citizen of the United States, residing at Paterson, in the county of Passaic,v State of New Jersey, have invented rcertain new and useful Improvements in T elephone-Excliange Systems, of which the following is a full, clear, concise, and exact description. v

This invention relates to telephone exchange systems and more especially to systems of the characterv wherein automatic switching apparatus is employed for the establishment of conversational connections.

ln certa-in types of telephone exchange ystems the automatic switching apparatus used for building up connections is arranged to be controlled in its operation by a controlling mechanism or sender, convenientlyv located at the central oilice in proximity to the switching apparatus itself. Where the system is one of the character in which the establishment of a connection involves the participation of an operator as well as the automatic seleftive switches it may be the duty of the operator to receive the designation by one means or another and to produce a record of the same on equipment, such as a keyboard, at her position. The record, once set up on the keyboard, is transferred therefrom to the register controlling mechanism and there recorded on controlling registers which later exercise a control over the selective movements ofn the automatic switches.

The operators keyboard., together with the individual mechanism and devices immediately associated therewith, are capaL ble of determining the transfer of a large number of diiferent wanted designations to the registers of a controlling sender. Moreover, the single keyboard at a given operators position is provided in common to a plurality of register senders and is fitted to transfer designatory records to any one of these register senders. The transfer' of the record from the keyboard to they several registers of the sender takes place over al control circuit which serves to interconnect the keyboard at the operators position with the particular one of the register senders that is taken for use at the time. This may be accomplished by means of impulses sent in codes, or in any other desired fashion, over the control circuit and directed to the TELEPHONE-EXCHANGE svsreiu.

Serial No. 525,986,l

several registers of thel sender. Since it is convenient to send the kimpulses over the Control circuit in a sequential order, bearing a relation to the order in which the digits or characters constituting the designation occur, it is desirable to associate the said control circuit with the resisters in succession in order that each register may receive its proper record.

The register controlling sender, having received the complet-e registra-tion identifying the number of the called line, next, becomes effective to control the select-ive switches in accordance with its registration- The directory numbers of subscribers lines are, of course, based on the decimal system, but, for reasons of economy, it is desirable to construct the switches and senders for `operation on a non-decimal principle. Therefore, the record established on the registers of the sender is non-decimal, yet the registration on each of the several registers bears a cert-ain and definite relation tothe digits of the called number.

lt is thus possible to greatly simplify the registers by decreasing` the total number of different combinations each register is cap-y able of recording. This is accomplished by providing a single controlling` device which eoacts with the registers to secure any eX- tent of control over the selective switch that the wanted number may require.

The object of the present invention is' to improve telephone systems. of the foregoingchara-cter by the use of a single controlling device which causes the association of the control circuit with the register controlling mechanism and which cooperates with said mechanism to determine the effect of the registration on the selective switches.

A feature of the invention relates to the provision of a relay which acts to associate the control circuit with the registers in suc cession while the record is being received, and which serves to modify the control of the registers over the selective switch to determine the extent of movement the selective switch is permitted to take under .the control of the registration on such registers.

Such other features'and advantages as' are contemplated by the present invention will be more clearly understood from the following detailed description and also from the appended claims.

Referring to the VAdrawing, the severaly ligures when taken in the order illustrated in Fig. 7, disclose so much of a telephone exchange system as is ne-cessary to an understanding ot the invention.

Fig. 1 shows a trunkline incoming from a distant otiice and terminating in an incoming automatic selector switch.

Fig. 2 illustrates the circuits of a iinal selector switch which cooperates with the incoming selector to extend connections to called subscribers lines in the oiiice where they are located.

Fig. 3 shows an operators keyboard and the individual equipment associated. therewith by means of which the designations of called subscribers lines are manually recorded.

Fig. l shows one ol' a plurality of trunk selector-sender selector units, the function of which is to automatically select the particular-incoming` trunk circuit assigned for use by the operator, to automatically select one of la plurality of idlesenders, and to associate the selected idle sender and the operators keyboard with each other and with said trunk circuit.

F igs.'5 and 6 illustrate one of the register senders located at the central oilice and which serves to control the incomingv and final selector switches in accordance with the designations` set up by the operator on her keyboard.

Fig. 7 shows the order in which the several figures are arranged.

General description 0f the system and l apparatus.

Thev automatic switching system disclosed in this application is particularly well adapted .for the disposition of inter-oiiice calls where the calls are received by a manual roperator in an originating` ollice 'from lines terminating, either directly in such originating oiiice, or lines which have been extended thereto," and which calls are destined for a subscribers line in a distant oiiice equipped with machine switching apparatus. The calling line having been extended to the A operator in theoriginating oliice, snc receives the desired number orally, and ou learning that it is intended for a subscribers line in av ydistant otlice equipped with selective switches, such as those shown in Figs. 1 and 2, communicates with the operator at such mechanical oiilce by means or" an order wire. The operator in the called oitice assigns an idle trunk for extending the calling line and which trunk terminates in an incoming selector switch, such as shown in Fig. 1. Also the A operator at the saine time communi- Cates the number of the called subscribers line tothe operator in the called oliice.

The selective switches shown in Figs. 1 andQ are of the power driven type in which the brush shafts are operated in a continuous movement from a constantlyoperating source of power, and which, during their movement, send out impulses in measurement of the distance traversed. These impulses reverted from the switch are received by register senders located at the central otlice. and on which registrations have previously been made in accordance with the designation oi' the called line. The register' senders respond to the reverted impulses, and when the proper number has been received, bring about a termination ot the movement E the switch by disconnecting the constantly operating source of power. A switch ol the general type and construction as those shown in Fig. l and Fig. 9. is illustrated and described in detail in the patent lio .Craft and Reynolds, 1,123,696, issued January 5, 1915.

A plurality of register senders, one ot' .1:

which is illustrated in Figs. 5 and 6, are provided at the omce, and any one of these that happens to be idle at the time the call is received Jfrom the distant office may be taken for use to record the designation of the called line as soon as the operator sets up the same on the keyboard at her position. Briefly, the register sender comprises a plurality ol relay registers each of which consists of a plurality of relays, some ot which are marginal and others sensitive. These relays and the circuits they control are shown in Fig. 6. ln Fig. 5 there is shown a controlline sequence switch 51() which first operates trom position to position to cause the association of the control circuit, which leads from the operators keyboard, with the successive registers shown in Fig. 6 for the purpose ol' transferring the registration 'from the keyboard to these registers. lVIoreover, there is provided for each sender a set of countingl relays shown in the upper part of Fig. 5, and astepping relay 520 which co-acts therewith to control over a fundamental circuit the selective movement of the switches in accordance with the character of the registration set up on the register relays.

The operators keyboard, shown in Fig. 3, consists of four rows oi' numerical keys; the thousands row 300, the hundreds row 301, the tens row 302 and the units row 303. Although the majority oi" the keys oi" each row have been omitted to save space in the drawing, it will be understood that each row oi keys consists of ten in number. By depressing' a single key in each of the tour rows on her board, the operator may make a record of the number ol' any line in the 10,00() line oi'ice of the exchange. The keys are of the locking type which mechanically lock in their depressed or actuated position and remain actuated until released by the energization of a common release magnet. There is provided one such magnet for each row of keys.

Iii-'i lll) Individual to the operators keyboard there is provided, a controlling sequence switch 310 and numerous relays, the purpose of which is to transmit impulses in the proper order ot sequence over a set of control conductors to the selected vidle register sender, which impulses :identity the character of the number written upon the keyboard. ln other words, the sequence switch 310 and its cooperating elements serve to transfer by means of impulses the numerical record set up by the operator on the keyboard over a control circuit to the sender where this record is recorded on the register relays.

The time required by the operator in setting up a number on her keyboard and for the same to.` be transferred to the controlling register sender is small as compared with the time that the sender may be necessarily associated with the switches in establishing a connection. This means that an operator through the agency of a single keyboard `may set up the records of a plurality of calls be- ,torethe senders taken vfor use in controlling the establishment of such calls are rendered free for further use. To this end the plurality of ot senders are available to the operator and may' be associated with her keyboard. The association is accomplished by means of `trunk selector and sender selecting units, one of which is shown in Fig. 4, there being a plurality of these for each operators position. Y

These: units each consist of a trunk selector switch 4127, which has access to terminals representing all ot the trunks 100 and 101 incoming to the operators position. Moreover, they sender selector switch of the unit, 428, has access to all of the senders. By any suitable arrangement the trunk selectorsender selector units may be allotted-for use, and when one is started in operation it operates to lind the trunk assigned by the operator and to nd an idle register sender and to associate the idle register sender thus selected with the operators keyboard. The switches 427 and 128are of the power driven type, similar in most respects to the switch referred to in the above-mentioned patent to Craftl and Reynolds.

The several sequence switches disclosed in the drawing, namely sequence switches 110,

210, 310, 410 and 510 may be of the` same construction as the one shown inthe patent to Reynolds and Baldwin 1,127,808, issued February 9, 1915. Y

Referring particularlyto the register senders shown in Figs. 5 and 6, there are seen to be five different registers for receiving the registration characterizing the number ot the called lines. The incoming brush register consists of relays 609, 611 and 612; the incoming`group register of relays 613 and 614; the final brush register of relays GOB, G1()- and 60,7; the final tens register of relays 605, 606, 603 and 615 and the inal units register ot' relays 600, 601, 602 and 604-. ils regards the incoming selector switch 125, shown in Fig. 1, the construction ot this switch is such that a maximum ot' five controlling impulses is sutlicient to control it in any selection. That is to say, lthe switch only has tive sets of brushes, and the grouping in the terminal bank is such that a brush section does not consist of more than 'live different groups. Therefore, in both the brush selecting and group selecting i'i'iovements of the incoming switch 125, a maximum ot tive impulses reverted from the switch to the sender is sutlicient to control any selection. This means that the incoming brush and group registersneed only to be capable ot registering ive different combinat-ions. The saine ris true of the nal selector switch 215 as regards its brush selecting movement` this switch likewise only being provided with five sets of brushes. .-lere.'however, each brush has access to 100 terminals, these 10() terminals being divided up into ten groups of ten terminals each.

vThe heal tens and units registers are arranged lil-ze the other registers of the sender to take only a maxium of live different settings. but as mentioned, the tens and units selections may involve more than live impulses. in order that the registers may control the .final switch when the selection involves a d' git greater than four, there is provided a translation or controlling relay 500, which operates provided the tens or units digit is greater than tour. The effect of this relay is to add live impulses to the value of the registration contained on the corresponding resister. .as will be brought out hereinafter,

the rela-y 500, which acts as a controlling and translating device for determining the influence of the register upon the extent of operation ot the selector switcl'iv during the establishment ot thel connection, also serves to cause the successive association of the control circuit, leading from the keyboard, with the several registers during the transfer oi the record.

Detailed description of operations n the a establishment of c, connection-the opera.- zcr recettes the call.

tomechanical ofiices, there to be handled by cordless B operators is shown and described in the patentto Lundell and Clark No. 1,342,823, issued J une 8, 1920.

The voperator in the ottice shown informs the originating manual operator that the trunk'100, 101 is assigned tor use, and that she may complete the connection over that trunk. At the same time, the operator making thev assignment depresses the key 119. A circuit is thereupon closed from ground through the contacts of said key, lower right contact 109 (1), winding oit sequence switch vmagnet 110 to battery. Sequence switch 110 moves out or' position 1, entering position 2 where it initiates the operation ot' an allotted sender selector unit in a manner to be taken up presently.

@poration of trunk selector and sender sclector.

When the sequence switch 110 moves into position 2, a circuit is established from 'ground' through the lower contact 108 (Ll-12%,), outer back contact o1' relay 104, lower right contact 111 (2), conductor 144, upper and lower contacts 419 (1), winding of relay 404 to battery. Relay 404 operates and closes a circuit from battery through the right-hand winding of relay 400, upper left contact 414 (l-l-ll/2), lower right contact 414 (14-3), left contact of relay 404, upper right contact 422 (1-1-3) to ground. Relay 400 becom'es energized and completes a circuit from battery through the winding of sequence switch 410, upper lett Contact 417 (1), outer right front contact of relay 400 to ground. Sequence switch 410 moves lout of position y1 and into position 2. As

the sequence switch advances from position 1 into position 2, the original circuit of relay 404 is opened at contact 419, but this relay remains energized in a circuit from battery through its winding and inner right contact, lower right contact 416 (1-1-4), commutator 459, brush 460 lto ground. With sequence switch 410 in position 2, both the sender selector 428 and the trunk selector 427 or" the allotted unit are started in operation, one to lind an idle lsender and the other to ind the incoming trunk 1 00, 101 which the operator has assigned for use in extending the connection.

The brushs'hat 450 of the sender selector is driven upwardly by means of the convstzuitly operating source of power, which is rendered eective by the updrive power magnet 407. The magnet 407 is energized in a circuit from battery through the winding of said magnet, right contact 417 (2), outer right front contact of relay 400 to ground. As the brushes 441,442, 443 and 444 of the sender selector encounter the terminals representing each register sender, a v-testis made 'to determinethe busy or idle condition of the corresponding sender. 1t the register sender corresponding to the first set of terminals, upon which the brushes of the switch 428 are standing, is busy, the test brush 443 tinds a ground potential thereon. Consequently, when the sequence switch 410 reaches position 2, a circuit is closed 'from battery through the right hand winding oit relay 400, upper right contact 411 (1443), upper left contact 411 (1-1-2), left front Contact of relay 400, upper right contact 12 y(155/4544), lower right contact 412 (149), conductor 451, brush 443 to the grounded test terminal, the ground being applied to such terminal in a manner to be explained hereinafter. It will be noted that the. circuit just traced for the relay 400 leads through a front contact of said relay and through the upper right contact 412, which is closed in position 1% to 4. This circuit is closed prior to the time the upper left contact 414 opens as the sequence switch 410 passes from position 1 into position 2, whereby ii'` the iirst sender is busy, the relay 400 remains locked in position 2 quence switch 410, and the circuit previously traced for the updrive power .magnet 407 is closed to advance the brush shaft 450 oli' the lirst set of terminals and on to the next in search ot an idle sender.

W'hen an idle register sender is found, the test brush 443 failing to tind a ground po tent-ial on the corresponding test terminal, opens the holdingcircuit yof relay 400 which becomes deenergized. Relay 400 opens the circuit oi the updrive power magnet 407 causing the brushes to come to rest on the terminals representing the selected idle sender. Moreover, relay 400 completes a circuit from ground through its outer right back contact, lower lett contact 423 (2), winding ot sequence switch 410 to battery. Sequence switch 410 advances out of position 2 and into position 3.

At the time sequence switch 4,10 reaches position 2, a circuit is also closed tor the lupdrive power magnet 405 ot the trunk selector switch 427. and the brush sha'tt 449 is moved upwardly to trail the brushes 435. 436, 437, 438, 439 and 440 over the terminals representing the different trunk circuits incoming trom the distant office. The circuit for magnet 405 is traceable from battery through the winding of said magnet, lower left contact 414 (2-}.3), lower right contact 414 (1-}-3), lett contact ol relay 404, right contact 422 (1-l-3) to ground. As the brush shaft 449 moves upwardly over the terminals of the bank, a test is made oit each set ot terminals to determine which one oit the incoming trunk circuits 100, 101 has been taken for use by the operator. )When the assigned trunk is reached, a circuit is closed from battery through the winding of relay 401, upper contact 424 (1%4-3), brush 437,

of seconductor-141, lower left contact.112 (2) of sequence `switch 110, upper right contact 112 (2-l-3), inner back Contact of relay 104, lower lett contactj113`(1-{10), lower right Contact 113 (2-I-B) to ground. Relay 401 operates inthis circuit and closes a (temporary locking circuit for itself traceable from battery, through the winding otsaid relay, lower contact 424 (1%.4-11), right front contact oi relay 401, upper left contact 422, (l-H'lt/) to ground. Relay 401 by energifting completes a circuit at its lett contact tor relay 402 and relay 402 becomes energized. Relay 401 at its right back contact opens the circuit `of relay 404, which becomes deenergized and in turn opens the circuit of the power magnet 405 causing the brush shaft 449 to cease its upward movement. Relay 404 in `addition to opening the power magnet circuit, completes a circuit trom ground throughits outer right contact, upper right contact 409 (3), winding of sequence switch 410 to battery, driving said sequence switch out of position 3 and into position 4. As sequence switch 410 leaves position 3%, the temporary holding circuit of relay 401 is opened at the lel't contact 422, but this relay is now held in a locking circuit traceable from battery through its winding, lower -contact 424 (1%-l-11), right iront Contact ot relay 401, innermost lett Contact of relay 402, brush 440, conductor 139, upper left contact 112 (2-1-11), upper right contact 112 (2-1-3), and thence to ground as described at the lower right contact 113.

lt was explained that the sequence switch 410 is driven from position 3 and into position 4 as soon as rela-y 404 deenergizes following the termination ot the operation of Y the vtrunk selector 427. This is on the assumption that sequenceV switch 410 has reached position 3 which it does immedi-` ately following the ltermination of the operation oi" the sender selector switch 428. lit should also be noted that the sequence switch 410 may pass from position 2 and into position 3 following the selection of a sender during the time that the trunk se# lector switch 427 is in operation without disturbing the function ot this Vlatter switch. lf the trunk selecto-r switch succeels in locating the assigned trunk prior to the time the sender selector switch 428 finds an idle sender, then sequence switch 410 remains in position 2 until relay 400 becomes deenergized. Thereafter it advances into position 3, and finding the relay 404 deenergized, immediately moves into position 4. l-lence the sequence switch 410 finally moves into position 4 after both selector switches have completed their functions regardless of which was the first to iinish its operation.

Tn position 4 of sequence lswitch 410, a

circuit is immediately closed from battery, through the right hand winding ot rela 400, upper right contact 411 `(145), lower right contact 411 (4-i-5), lower lett contact 420 (4-1-5), outermost lleit contact of relay 402, brush 485, conductor 143, lower left contact 120 (2-1-11), upper leit contact 120 (2) to ground. Relay 400 becomes operated and closes a circuit from ground through its outer right front contact, upper left contact 417 (4), winding of sequence switch magnet 410 to battery, advancing said sequence switch out of position 4 and into position 5. Relay 400 remains `energized in position 5 ot the sequence switch in the circuitabove traced.

Ait the time the relay 400 deenergizes, when the sender selector finds an idle register sender, a circuit is closed as follows temporarily to render the selected sender busy to other switches: ground, through the left back contact of relay 400, upper right Contact 412 (1%4-4), lower right Contact 412 .(1+9), conductor 451, brush 443, and thence to the multiples of the terminals representing-'the selected sender. Later when the sequence switch 410 moves from position 2 and into position 3, as previously explained,` the busy ground potential is furnished over the lower left contact 412, closed in position 2% to position 81/4, lower right contact 412 (1-f-9)', and thence to the multiple terminals in the bank of the sender selector switch 428.` Immediately'after the sequence switch 410 reaches position 4, a i

circuit is closed from ground through the right iront Contact ot relay 402, lower right contact'421 (4-i-6), upper right contact 421 (4-I-5),` brush 441, conductor 445, upper left contact 518 (1) of sequence switch 510, right hand winding of relay 5.01`to battery. Relay 501 operates in this circuit andl completes a circuit from ground through its left front contact, upper lett contact 507 (1), winding of sequence switch magnet 510 to battery. The sender sequence switch 510 moves into position 2, thus preparing the circuits of the sender for receiving the incoming registration from the operators keyboard. rThe re lay 501 upon energizing closes a circuit from battery through its right `hand winding and right contact, conductor 447, brush 443, and thence to ground at the contact 412 as previously traced. Relay 501 also closes a circuit from battery through its right hand winding, thence throughy its'leit hand winding, upper lettcontact 508 (2-1-18) to ground. This latter circuit, howeveigis not sufficient to maintain the relay 501 energized when ground is lremoved from the conductor-447. In other words, the relay 501 remains energized only so long as ground is held on the conductor 447 until sequence switch 410 leaves position 8%, Tl purpose of the circuit through the left hand winding of relay position prior to the time that sequence switch 510 advances through position 18.

The operator records the @all number on lier keg/board.

, At the time the originating manual operator requests the assignment of an idle trunk, she also orally communicates to the operator in the mechanical oiiice the number of the called subscribers line. This number is thereupon set up on the operators keyboard. Assume, for example, that the number of the wanted line is 6321, the last two digits of which it will be noted are less than four, signifying as will be seen hereinafter, that no translation is required with respect to the tens and units selecting movements of the final selector switch 215. Accordingly, the operator depresses the No. 6 thousands key.304, the No. 3 hundreds key 305, the No. 2 tens key 307, and the No. 1 units key 309. These keys lock in their depressed positions as fast as they are actuated,.and upon the depression of a key in each row, the common row contacts 315, 316, 317 and 318 are opened. Upon the depression of the iirst key 304, a circuit is closed from battery through the resistance 344, windingof relay 345, contact 348 (18%-i-G) of sequence'switch 310, right contacts ot key 304, conductor 358 to ground. Relay 345 does not energize since its winding is shunted by a circuit from battery through the resistance 344, left Contact of relay 345, conductor 359, through contacts 316, 317 and 318 in parallel, right contacts of key 304, conductor 358 to ground. The contact 315 lopened'whenl key 304 was depressed, but

since none of the remaining keys in the other three rows are actuated, contacts 316, 317 and 318'are still closed. Upon the depression of the key 305 in the hundreds row, contact 316 is opened, but contacts 317 and 318 are still closed to maintain the shunt around the winding 345. However, when the last key 309 is depressed and the last row lcontact 318 is opened, all possible paths tor maintaining the shunt around the winding 345 are opened and the said relay becomes energized. The energizing circuit of relay 345 may be found by inspection to lead through the right hand contacts of each lof the depressed keys so that said relay would remain operated as long as any key in any row is in its actuated condition.

As soon as therlast key is depressed and the relay 345 is operated, a circuit is closed from ground through the right front contact of said relay, upper right contact 343 (1), outer right back contact of relay 320, conductor 360, upper left contact 326 (1), lower right contact 326 (1), conductor 354, lower lett and upper left contacts 413 (5), middle left contact of relay 402, brush 438, conductor 140, lower left contact 116 (2), winding of sequence switch magnet 110 to battery. VThe sequence switch 110 thereupon advances out of position 2 and into position 3. As sequence switch` 110 reaches position 2%, the holding circuit of relay 401 previously traced is shifted so that it now leads to `ground through the lower right contact 112 (2%-1-18). Moreover, as sequence switch 110 leaves position 2, it opens at the upper lett contact 120 the holding circuit hereinbefore traced for relay 400. Relay 400 thereupon releases its armatures and a circuit is closed from ground through the outer right contact of said relay, lower left contact 423 (5), winding of sequence switch magnet 410 to battery. Sequence switch 410 leaves position 5 and moves into position 6.

With sequence switch 410 in position 6, a circuit is closed from ground to the right front Contact of relay 402, winding of relay 403, lower contact 415 (6), conductor 353, upper right. contact 319 (1-1-5), upper left Contact 319 (1), lett hand winding of relay 320 to battery. Relay 320 operates and locks in a circuit through its left hand winding and lett contact. Relay 403 also operates in series with relay 320 and closes a circuit from battery through the right hand winding of relay 400, upper left and upper right contacts 414 (6-1-7), left con tact of relay 403 to ground. Relay 400 becomes energized and closes a circuit from ground through its outer right contact` upper lett contact 417 (6), winding of sequence switch 410. Sequence switch 410 moves into position 7 and relay 400 remains energized. In position 7 the lower left contact 415 is opened, but the energizing circuit of' relays 320 and 403 is maintained over the upper lett contact 415 and the inner right contact of relay 400. The relays 400 and 403 by energizing at this time extend the three impulse control conductors 357, 356 and 355 through the brushes ot the Sender selector switch 428 to the selected register sender. Thus the operators keyboard is effectively associated through the medium of the sender selector with the sender shown in Figs. 5 and 6.

Peg/Stratton of called number on the register sender.

When relay 320 operates a circuit is effective for transinittinfrn code ot' im ulses characterizing the thousands digit to cause a corresponding registration on the registers of the sender. ln position 2 of the sequence switch 310, a circuit is first closed from battery, resistance 340, upper contact 311-1 (2), winding voit relay 339 to ground.

' Relay 339, however, remains inert inasmuch as its ywinding is shunted by a path leading through the outer back contact of said relay and the normal contact at the left hand armature ot' relay 338 to ground. Another circuit is closed Jfrom battery through. the low resistance 350,` upper lett contact 351 (Ml-0), lett contacts of thousands key 301i, conductor 361., lower y lett contact 327 (NAA-2), lowerleit contact 326 (1S/(+5), conductor 356, inner right contact of relay 403, brush alii, conductor 445, lower right contact 513 (13d-k2), conductor 529, right hand windings of relays 609 and 612 to ground. Relay 309 is marginal, but since only the low resistance 350 is included in the ii-cuit, this relay becomes energized. llelay y612 also becomes energized. The relays (209 and 61.2 locli in circuits from bati'ory through theirleft hand windings and lett contacts, thence over conductor 536, upper right contact 513 (1344-14) to iground. Another circuit closed 'from grouinfl through the inner contact ott' relay 339, lett hand low resistance winding of relay 333, upper left contact 337 (2), midille contacts of hey 304. conductor 362, lower right contact 329 vconductor 357,

outer r ht contact ot relay e103, brush 4:42,

relay 333 is included in series therewith,`

' is becomes energized "and locks in a circuit When relay operates, it closes u circuit lroin battery, through the upper right contact (2), lowT resistance 335,'right con.- tact ot' relay 338 high resistance 331, lower lett contact 330 (2-l-5), conductor 355, lower left and upper lett contacts 411 .(6--1-7). ylett front contact of relay 400, lower right and upper right contacts 4,13 (t3-P7), brush esta, conductor 448, left hand winding oi? relay 613, conductor 54.3, lower leit contact 515 (2), winding of relay 502 to battery. Due to the inclusion of the high resistance 331 iu the circuit. traced, marginal relay 313 does not receive suicient current to energize. Relay 502, however, operates and closes a circuit -from battery through the winding ot sequence switcli magnet 510, iront. contact ol relay 502, lower rightand upper right contacts 505 (2), right back contact ot relay 500, lower Contact 503 (1-l-5) to ground. Se? quence switch 510 moves out ot position 2 and into position-3. `lVhen sequence switch 511.0 leaves position 2, it opens at its upper right contact 5i@ the holding circuit otrelay 333 and at its lower lett contact 515 opens the circuit oit relay 502. Relay 338 upon deenergizingcompletes a circuit from ground through the norinai contacts at its lett hand armi-iture, outer armature andy iront contact ot relay 339, upper right oontact 321 (2), winding of sequence switch magnet 310 to battery, driving said sequence switch out ot position 2 and into position 3. Sequence switch. 310 on leavingposition 2, opens the circuit of relai.y 339 permitting the saine to deeuergize. In the' nu'inner described, the incoming above brush register has been positioned in accordance with. the designation set up on the operators keyboard by .means of code impulses transmitted from the keyboard over the impulse control. circuit to thesender. .lhe next operation that will take place is the transmission in a similar manner of iinpulses tor setting `the incoining group regter. With sequence switch 310 in position 3 a circuit is closed `from battery through the low resistance 340, lower right contact 341 (3), winding of relay 322 to ground. Relay 322 does not operate because it is shunted by a path leading through its inner back contact and the norinal contacts at the lett hand armature of relay 323 to ground. Another circuit is closed from battery through the low resistance 350, upper left contact 351 (Ll-6), lett hand contacts of key 305, upper left contact 329 (23/4-3), conductor 357, outer right contact oit relay 403,brush 4&2, conductor elle, lower right contact 516 (Ll-5), upper lett contact 517 (2%-l-3), conductor 531, right hand windings of relays 003 and 607 to ground. Since only the low resistance '350. is included in this circuit,` nuirginal relay 608 becomes operated and also the sensitive lrelay 60T. These two relays lock -incircuits through their left hand windings and left contacts over conductor 536to ground at the upper right contact 513 (lyi-l-lllf). Another circuit is also closed fromiground through the outer right contact ofvrelay 322, right hand low resistance winding of relay 323, upper lett contact 333 (3), middle contacts of key 305, conductor 362, upper right contact 327 lower lett contact 326 (1%-1-5), conductor 356, inner right contact of relay 403, brush 441, conductor 445, lower left contact 5.18

(2%-l-3), conductor 530, left hand winding of relay 610 to battery. Since only the low resistance winding ot relay 323 is included in series with marginal relay 610, this latter relay becomes energized.` Relay 610 locks in al circuit through its right hand winding and inner right contact to the grounded conductor 536. Relay 323also operates and closes a locking circuit tor itself and the register relay 610 through the left hand front contact ot said relay 323 to ground. Relay 323 alsoopens the shunt around re* lay 322 and this latter relay becomes energized in the circuit previously traced. l/Vith relay 323 operated, another circuit is completed from ground through the contactJ 324 (3), low resistance 325, right-contact ot relay 323, high resistance 331, lower contact 330 (2-l-5), conductor 355, and thence as previously traced to the conductor 448, right hand winding oi" relay 614, conductor 537, right Contact 514 (3), right hand winding ot relay 500 to battery. Due to the high resistance 331, relay 614 cannot operate. Re-

lay 500, however, attracts its armatures and a circuit is closed :trom ground through the lower left Contact 503 (1-r-5), right front contact of relay 500, upper lett and lower left contacts505 `(3), back contact of relay 502, winding of sequence switch 510 to battery. Sequence switch 510 moves out of position 3 and into position 4, and in so doing opens the previously traced circuit for relays 323 and 500. Relay 323 upon deenergizing closes a circuit from ground through its lett normal contacts, inner front Contact of'relay 322, lower right contact 321 (3), winding` of sequence switch magnet`310 to battery. Sequence switch 310 moves from` position 3 into position 4, and opens cuit of relay 322. Y

lWith sequence switch 310 in position 4, the previously traced circuit for relay 339 is closed, but this relay does not energize so long as its winding is shunted by the normal contacts of relay 338. Vith sequence switches 310 and r510 in positions 4, a circuit is closed from gro und through the inner contact of relay 339, left hand winding of relay 338,- upper right contact 337 (4), middle contacts of key 307, conductor 364, upper left contact 328 (4), conductor 357, and thence as previously traced to the conductor 446, lower right Contact 516 (1-l-5), upper left contact 516 (3%-1-4), conductorl 533, left hand winding ot relay 606 to battery. Although relay 606y is marginal, it operates the cirsince only the low resistance winding of relay 338 is included in the circuit therewith. Relay 606 locks in a circuit through its right hand winding and inner right Contact, conductor 535, upper left contact 513 (1%-1-14) to ground. Relay 338 also operates and locks through its lett front contact as previously described. Relay 338 also removes the shunt from around the winding ot relay 339 and this latter relay attracts its armatures. further circuit is completed from battery through the upper left contact 363 (4), low resistance 335, right contact of relay 338, high resistance 331, lower lei't contact 330 (2-l-5), conductor 355, and thence as traced to the conductor 448, right hand winding of relay 615, conductor 542, lower right contact 515 (4), winding of relay 502 to battery. Due to the high resistance 331, the marginal relay 615 does not operate. Relay 502, however, becomes energized and closes the above traced circuit for driving sequence switch 510 into position 5. Sequence switch 510 on leaving position 4, opens the circuits o1 relays 502 and 333. Relay 338 upon deenergizing closes a circuit as previously traced over the upper right contact 321 for driving sequence switch 310 into position 5.

)lilith sequence switch 310 in position 5,

the circuit here-inbefore described is completed for relay 322, but this relay is also shunted at the normal contacts of relay 323. Furthermore, a circuit is closed from ground through the outer contact of relay 322, left hand winding ot relay 323, upper right contact 333 (5), middle conta-cts of key 308, conductor 364, upper right Contact 326 (5), lower left Contact 326 (13A-t5), conductor 356, and thence as previously traced to conductor 445, lower right contact 51S) (4%-l5), conductor 527, lett hand windingl of relay 601 to battery. Gnly the low re sistance winding of relay 323 is included in the circuit traced, and consequently the marginal relay 601 becomes operated. Relay 601 locks in a circuit through its right hand winding tothe grounded conductor )relay 323 also operates, locks from ground through its lett front contact and removes the shunt -lrom around relay 322, whereby this latter relay becomes energized. A :turther circuit is closed from battery through the low resistance 350, right hand contact 351 (1-l-6), high resistancey 352, lett hand contact of key 309, upper right contact 329 (437,:-1-5), conductor 357, and thence as previously traced to conductor 446, lower right contact 516 (1-1-5), upper right contact 517 (4%-l-5), conductor 532, right hand wind ings of relays 600 and 602 to ground. Since the high resistance 352 is included in the circuit traced, relay 600 ails to energize. The sensitive relay 602 attracts its armatures and locks in a circuit through its lett hand winding tothe grounded conductor 535. With relay 323 operated, a circuit is completed from ground throughthe lower left due to the high resistance 331, the marginal relay 604 does not receive sutlicient current to become energized. Relay 500 upon. attracting its armatures closes the circuit previously traced for advancingfthe sequence switch 510 out of position 5 and into position 6. Sequence switch 510 on leaving position 5 opens the circuits of relays 500 and 323. Relay 323 on deenergizing closes the circuit already described for advancing sequence switch 310 out of position 5 and into position 6. rll`he complete record has now been transferred from the operators keyboard andvset up on the register relays of the controlling sender. The operators keyboard is required no longer in connection with the present call and may be released in order that it may be tallren for use in connection with subsequent ca ls.

Release of the opcmrtors keyboard.

When the sequence switch 310 reaches position 6, a circuit is established from battery through the contacts 346, conductor 365, through the key release magnets 311, 312, 313` and 314 in parallel to ground. These magnets become energized and permit the depressed keys in `their respective rows to berestored topnormal. y `When the last key has been released, all parallel branches for maintaining the energization of relay 345 are opened, and this relaybecomes deenergized. `Relay 345 completes a circuit from Iground through its right back contactupper left contact 342 (6), winding of sequence switch magnet 310 to battery. `Sequence switch 310k leaves position 6 and moves into position 8. 1n positions S and9 a circuit is closed from battery through the winding of sequence switch magnet 310, lower left contact 321 to ground whereby said sequence switch continues to move into position 10, which is its second normal position corresponding to position 1. All parts of the operators keyboard andits individual equipment are `now fully restored and in readiness to control the transfer of another record tc a register sender when associated therewith.

l-rt .the time sequence switch 310 leaves position 5, it opens at the upper right contact 319, the circuit which up to this time has been maintaining the energization cf relays 320 and 403. These relays become deenergized, relay 403 opening the circuit of relay 400. Relay 400v releases and completes a circuit from ground through its outer right bach contact, lower left contact 423 (7), winding of sequence switch magnet 410 to battery. Sequence switch 410 is driven into position 8 where y it prepares the fundamental circuit leading from the sender through the brushes of the trunk finder switch 427 to the incoming selector switch 125. l Opel/"ation of the incoming selector switch. The fundamental circuit Lfor controlling the brush selecting operationof the incoming selector switch is now established and may be traced from battery through the right hand winding of relay 104, lower contact 107 (1d-4), upper right contact 105 (3d-7), conductor 143, brush 435, outermostl left contact of relay 402, lower right con.- tact 420 (3), brush 441, conductor 44,5, upper left contact 519 (6), winding of stepping relay 520, bach contact of the 0 counting` relay 521 to ground. Relay 104 attracts its armatures and a circuit is closed from ground through the lower contact 108 (1A-12ML), outer front contact of relay 104, lower left contact 109 (2a-3),l winding of sequence switch 110 to battery.` Sequence switch 110 moves into position 5 andrelay 104 is maintained energized in a locling circuit from battery through its right hand winding, upper left contact 113 (4447)?, lower left Contact 113 (1-1-10), in'nerv frontcontact of .relay 104, lower contact 105 (4-I-9), upper right contact` 105 (3-l-7), c'onductor 143, and thence to ground as traced over the fundamental circuit. With sequence switch 110 in position 5, the updrivc power magnet 122 is energized to cause the upward movement of the brush shaft 145. The circuit of this magnet may betraced from battery through the winding thereof, Contact 114 (5), outer front contact of relay 104 to ground at the lower contact 108 (141m). i

r1`he stepping relay 520 which also energizes in the fundamental circuit completes a circuit from ground through the lower right contact 513 (6), conductor 545, armature and contact of the stepping relay 520, conductor 546, lower left contact 511 (6.), upper right contact 512 (6)7 conductor 547, right front contactof relay 612, left front Contact of relay 611, outer right front contact of relay 609, conductor 616, thence to conductor 555, Fig. 5, back contact of counting relay 548, wnding of relay 568 to battery. Relay 568 becomes operatedv and closes a circuit throu'gh its winding and the winding of relay 54S in series, Contact of relay 563, upper contact 506 (6) to ground. The relay 548, however, is shunted foo y vby* the circuit previously traced through the Contact of said relay 520, and therefore does not energize at this time.

` It will be noted that the conductors, such as conductor 616, leading from the contacts of the several register relays ink Fig. 6, terminate in small circles which contain the ordinals from 0 to 4. These conductors in practice are connected to the correspondingly designated conductors at the armatures of the counting relays shown in Fig. 5, but have been omitted from this disclosure in order to avoid unnecessary complications. As the brush shaft 145 of thel incoming selector switch moves upwardly under the influence of the power magnet 122, the commutator brush 133 encounters the rst `metallic circuit' of commutator 1361, and fa lcircuit is completed from battery through the right hand winding of relay 104, upper left Acontact 113 (4-1-7), lower left contact 113 (1+10), inner front contact of relay 104, lower right contact`105 (4-1-9), upper right contact 107 (4%-i-5), commutator 136, brush 133 to ground. This circuit maintains the energization of relay 104 and.

shunts the stepping relay 520 at the sender.

' )telay 520becomes deenergzed and opens l133y engages an insulated segment of the commutator, the shunt is removed from the winding of relay 520 and this relay becomes energized `to complete the stepping circuit now byway ofl conductor 616 through the front contact of relay 548, back contact of the No. 2 counting relay 549, winding of relay, 550, to battery. Relay 550 operates and closes a circuit for itself and relay 549 as above traced, but relay 549 being shunted does notI energize at this time. For each brush tripping yposition passed over by the selector switch, the stepping relay 520 is shunted in the manner described, and an additional-pair of counting relays are energized and locked. lFinally, when the 0 countingrelay 521 becomes operated, it opens the fundamental circuit and also completes a circuit from ground through its front contact, conductor 551, lower contact 507 (6), Winding ofsequence switch magnet 510 to battery.v The sender sequence switch 510 leaves position 6 and moves into position 8. On passing from position 6 to position 8, the Contact 506 is opened, permitting alll energized counting relays to become released.

As soon, following the opening of the fundamental circuit at the 0 counting relay 521, as the brush 133 engages the next insulating segment of commutator 136, the holding circuit of relay 104 is opened and contact 115 (G4-8) to ground. Magnet 124 n operates to rotate the tripping spindle preparatory to tripping the selected set of brushes on the subsequent upward move- \ment of the brush shaft 145.

The fundamental circuit is again closed for controlling the group selecting movement of the incoming switch, and 1s traceable over the same path as previously described. Relay 104 becomes energized and closes a circuit from ground through the lower contact 108 (Lf-12%), outer front contact of relay 104, lower left contact 109 (6), winding of sequence switch magnet 110 to battery, driving the sequence switch into position 7. In position 7, the relay 104 rcmains locked in the fundamental circuit over Contact 113 as previously explained. The updrive power magnet is energized in a circuit from battery through the winding of said magnet, Contact 114 (7), outer front contact of relay 104 to ground at the lower contact 108. The upward movement of the brush shaft 145 is resumed, tripping the selected set of brushesand trailing the same over the terminals of the bank.

The stepping `relay 520, which also energizes in the fundamental circuit in series with relay 104, completes a circuit from ground, lower left contact 513 (8-1-12), conductor 546, contact of the stepping relay 520, conductor 545, upper left and lower left contacts 512 (8), conductor 552, left back contact 613, outer right back contact of relay 614, conductor 617, thence to conductor 554, Fig. 5, upper and lower contacts 504 (6-l-18), right back contact of relay 500, upper contact 503 (G4-18), windin` of the 0 counting relay 522 to battery. elay 522 operates and completes a locking circuit for itself through the winding of relay 521, Contact of relay 522 to ground at the upper contact of relay 506 (8). Relay 521, however, does not energize so long as its winding is shunted by the circuit through the contact of the stepping relay 520.

As the brush shaft 145 advances the brushes 126, 127 and 128 into operative relation with the first group of terminals to which these brushes have access, the group selecting commutator brush 134 encounters vin its trunk hunting movement.

the rst metallic segment of the commutator 137. This results in the closure of a circuit from battery through the right hand winding of relay 104, upper left contact 113 (447), lower left Contact 113 (14-10), inner front contact of relay 104, lower contact 105 (44-9), upper left contact 107v (6%:4-7), commutator 137, brush 134 to ground. elay 104 is maintained energized, but the stepping relay 520 is shunted and releases its armatureto removethe shunt from the winding of the 0 counting relay 521. Relay 521 therefore operates and opens the fundamental circuit and also closes the circuit above traced at its front contact for advancing` the sender sequence switch out of position 8 and into position 10. On passing from position 8 to position 10, the sequence switch 510 opens Contact 500 and relays 521 and 522 release.

As soon, following the opening of the fundamental circuit at the sender, as brush 134 engages the insulating `segment of commutator 137, the holding circuit of relay 104 is opened and this relay becomes deenergized, thereby opening the circuit of the `power magnet 122, permitting the brush shaft 145 to cease its upward movement. ltelay 104 alsoV completes a circuit over the lower contact 103 and its outer back contact and upper leftf contact `109 (7) fordriving sequence switch 110 out of position 7 and into position 8. l

` ln position 3 of sequence switch110, a circuit is immediately closed from battery through the left hand winding of relay 104, right contact (24-9), left hand contact 106' (3481/4) toground. `Relay 104 operates and locks in the following circuit, providing t-he rst trunlr in the group, upon. the terminals of which the brushes 126, 127 'and 123-are now standing, is busy: battery, through the right hand winding of said relay, lower contact 107 (84-17), lower contact (44-9), inner front Contact of relay 104, lower left contact 113 (14410), upper right contact 113 (S4-15%,), brush 123, to ground on the busy test terminal. Relay 104 by remaining` energized completes a cir-- cuit from ground through the lower contact 108 (14-121/4), outer front contact of relay 104, lower left contact 109 (8), winding of sequence switch magnet 110 to battery. Sequence switch 110 moves into position 9 and relay 104 remains energized in its latter circuit, although the original operating circuit through its left hand winding is opened. `With sequence switch 110 in position 9 and relay 104 operated, a circuit is closed for the updrive magnet 122 to cause the continued operation of the switch Y The circuit `for magnet 122 leads as previously traced over the contact 114, now closed in position 9, and through the front contact of relay 104. Wfhen the brushes 126,f 127 and 128 encounter the terminals 129, 130 and' 131 of the first idle trunk in the group, no ground potential being found on the test terminal, the circuit of relay 104 is opened and this relay deenergizes to open the circuit of the power magnet 122. Relay 104 also completes a circuit fromground through the lower contact 103 (14-121/1), outer back contact of relay 104, upper left contact 109 (9), winding of sequence switch magnet 110 to battery. Sequence switch 110 moves out of position 9 and into position 11 where the 'fundamental circuit is extended through to the iinal selector switch ready for controlling `the brush selection operation there- Operation of the jim/Z selector switch.

rthe fundamental circuit may be traced from battery through the winding of relay 201, contact 207 (1), upper left contact 211 (154-6), conductor 229, terminal 129, brush 123 lower right contact 120 (114-15), lower left `contact (24-11), conductor 143, brush 435, outermost left Contact of relay 402, right contact 420 (8), brush 441, conductor 445, upper left contact 519 (10), winding of stepping relay 520, bach contact of relay 521 to ground. Relay 201 becomes energized and closes a circuit from. ground tl'irough its left front contact,"contact 203 (1), winding of relay 200 to battery. Relay 200 operates and locks in a circuit from battery through its winding and left contact, test terminal 131, test brush 123, upper right contact 113 (84151/l ),lower right contact 113 (104-17) to ground. It will also be noted that the ground connection from the contact 113 maintains the multiples of test terminal 131 busy to all other incoming selector switches. Relay 200 completes a circuit from ground' through its right front y Contact, upper left contact 204 ('1), winding of sequence switch magnet 210 to battery, driving saidk sequence switch out of positicn 1 and into position 2. `1n position 2 relay 201 remains locked in a circuit from battery through its winding and right contact, lower right Contact 209 (14-6), upper left contact 211 (154-6), and thence over the fundamental circuit as traced to ground. 1l/Vith relay 201 energized and sequence switch 210 in posit-ion 2, a circuit is closed for the power magnet 213 to cause the upward movement of the brush shaft 231 for selecting the proper set of brushes. The circuit of magnet 213 may be traced from battery through the winding thereof, Contact 205 (2), left front contact of relay 201 to ground. 4

The stepping relay 520, also operating in the fundamental circuit, closes a circuit from ground through the lower right contact 513 (10), conductor 545, contactof stepping relay 520, conductor 546, lower contacts 511 (10), conductor 558, right front VContact of register relay 607, left front contact of relay 610, outer right front contact of relay 608, conductor 618, and thenceto conductor 555, F 5, back contaetof relay 548 winding of relay 568 to battery. Relay 568 operates and completes a locking circuit for itselfin relay 548, but theI latter relay does not energize due to the shunt around its winding at the contact of the stepping relay 520.

For each brush tripping position passed over by thev final selector switch, a circuit i is closed from battery through the winding and right contact of relay 201, lower rightcontact 209 (11-6), upper right contact 211 (1e/ft2), commutator 226, brush 223 to ground. The closure of this circuit maintains the energization of relay 201 and also shunts the stepping relay 520 in the fundamental circuit. As previously eX- plained, the shunting action of the stepping relay 520 causes the successiveenergization of the counting relays, and when finally the proper set of brushes have been reached,

the, 0 counting relay 521 is operated and thefundamental circuit is severed at the sender. Relay 521 in addition completes a circuit through its front contact, conductor 551, lower right contact 507 (10), winding of sequence switch 510 to battery, driving the sequence switch out of position 10 and into position 12.

YVhen, following the opening ofthe fundamental circuit at the sender, the brush 223 engagesthe next insulated segment of the commutator 226, the circuit of relay 201 is opened and lthis relay releases, opening the circuit ofthe power magnet 213, causing `the brush shaft to come to resttemporarily. vRelay 201. also closes a circuit through its left back contact and the upper right vcontact 204 (2) for driving sequence switch 210 out of position 2 and into posilsaid sequence switch moves out of position 3 and into position 4. In position .4 relay 201 remains locked through its winding and front contact over a circuit similar to the one hereinbefore described. )Vith relay 201 operated, and the sequence switch 210 in position 4, the updrive power magnet 213 is energized and the brush shaft, 231 moves upwardly tripping the selected set of brushes and trailing the selected set of brushes 216, 217 and 218 over the terminals of the bank to select the proper group of ten sets of terminals.

The stepping relay 520 at the sender, also operating in series with relay 201 in the fundamental circuit, completes a circuit from ground through the lower left contact 513 (8-1-12), conductor 546, contact of relay 520, conductor 545, upper left contact 512 (12), upper left co'ntact 511 (12), conductor 556, right back contact of register relay 603, outer right front contact of relay 606, conductor 619, thence to conductor 557, Fig. 5, back contact of relay 549, winding of relay 550, to battery. Relay 550 operates and prepares a holding circuit for itself in series with the winding of relay 549 to ground at the upper left contact 506 (12). Relay 549, however, being shunted by the stepping relay 520 does not yet operate.

As the brush shaft 231 moves upwardly, driving the brushes 216, 217 and 218 over each succeeding set of ten line terminals, the brush 224 makes engagement momentarily with a metallic segment of the group selecting commutator 227. At each closure of the brush 224 a circuit is completed from battery through the winding and right contact of relay 201, lower contact 209 (1-1-6), upper right contact 209 (33744-4), commutator 227, brush 224 to ground. This circuit holds the relay 201 energized and shunts the stepping relay 520. When the brushes have reached the proper group of ten terminals, the 0 counting relay 521 finally operating opens the fundamental circuit at its left back con tact, and at its left front contact closes the circuit traced for driving the sender ysequence switch out of position 12 and int( position 14.

As soon, after the fundamental circuit is opened, as brush 224 disengages the conducting segment of commutator 227, relay 201 becomes deenergized and opens the circuit of the power magnet 213. Relay 201 furthermore completes a circuit over its left back contact and the upper right contact 204 (4) for driving sequence switch 210 out of posi tion 4 and into position 5.

Lastly, the fundamental circuit is closed in the manner hereinbefore traced for conftrolling the units selective movement of the switch to direct the brushes 216, 217 and 218 on to the terminals of the called sub` scribers line. Relays 201 and 520 operate in the fundamental circuit and the former of the relays closes a circuit similar to the one hereinbefore described for driving sequence switch 210 out of position 5 and into position 6. With sequence switch 210 in position 6 and relay 201 energized, the

llfi

power magnet 213 again has its circuit closed over contact 205 andthe left front contact of relay l2,01.` y i Stepping relay 520 on energizing in series with relay 201 closes a circuit from ground through the lower right .contact 513 (14), conductor 545, contact of relay 520, conductor 546, lower left and upper right contacts 511 (14), conductor 558, right front contact of register' relay 602, left front contact of relay 601, outer right back contact ofrelay 600, conductor 620, thence to conductor 526, Fig. 5, baci; contact of relay 523, winding of relay 524 to battery. Relay 524 operates and prepares a locking circuit for itself in series with the winding of relay 523, but the relay 523 cannot operate until the shunt is removed at the Contact of the stepping relay 520.

The brush shaft 231y moves upwardly and for each set of terminals traversed b-y the brushes 216, 217 and 218, the commutator brush 222 makes engagement with a metallic segment of the cominutator 228. This en gageinent results in the closure of the circuit 'froni battery thronghthe winding and right contact of relay V201, lower contact 209 (Hi-6), contact 212 (53744-6), commutator 228, brush 222 to ground. Relay 201 remains operated, but the stepping relay 520 is shunted.v When the selected set lof terminals 219, 220 and 221 in the selected group y of tens have been reached by the brushes,

the .0 :counting relay `521 operates and opens the fundamental circuit. Shortly thereafter brush 222 disengages the corresponding metallic segment of commutator 228. Therefore, the holding circuit of relay 201 opens, and this relay becomes deenergized to open the circuit of the power magnet 213 causing the switch shaft to cease its upward movement. Relay 201 deenergizing also closes a circuit at its left back contact and the upper right contact 204 for driving sequence switch 210 out of position 6. Relay 521 on operating also closes a circuit through its front contact, conductor 551, lower right contact 507 (14), winding of sequence switch magnet 510, driving said switch out of position 14 and into position 16.

Release of the register sender.

.right conta-ct 423 (8), winding of sequence switch' vmagnet 410 'to battery. Sequence switch 410 leaves position vand movesV into eases le realities Qi essere@ Swich 410, a circuit is closed from battery through the winding of said sequence switch, lower left contact 423, outer right back contact of relay 400 to ground, whereby the sequence switch 410 is moved out of position 9 and into position 10. ln this position the .sequence switch 110 of the incoming selector switch 125 is advanced out of position 11. The circuit for causing this advance may be traced from battery through the winding of sequence switch magnet 110, lo-wer left contact 116 11), conductor 140, brush 438, middle left contact of relay 402, upper contart 426 (10), lower contact 426 (6%-I-10) to ground. Sequence switch 110 on leaving position 11 opens at its upper left contact 112 the holding circuit of relay 401. Relay 401 becomes deenergized and opens the holding circuit of relay 402. With relay 402 released, a circuit is closed from battery through the winding of sequence switch magnet 410, upper left contact 423 (4-1-10), right back contact of relay 402 to ground. Sequence switch 410 moves into position 11 where the brush shafts of the switches 42,7 and428 are restored to their normal positions.

yThe sender selector 428 is released by means of the downdrive power` magnet 408, the circuit of which is closed from battery through the winding of said magnet, right contact 418 (11) to ground. The trunk selector switch 427 is restored to its normal position by means of the downdrive power magnet 406, the circuit of which may be followed from battery through the winding of said magnet, upper left and upper right contacts 412 (114-12), left back contact of relay 400 to ground. If the sender selector 428 is the first to reach its normal position, or as soon after the restoration of the trunk selector 427 as said sender selector does reach its normal position, a circuit is closed from battery through the winding of sequence switch magnet 410, lower right Contact 409 (3-1-11), normal position segment 433, brush 432, upper left contact 418 (3%4-18) toground. Sequence switch 410 thereupon moves out of position 11 and into position 12. If at this time the trunk selector switch 427 has reached normal, or as soon thereafter as said switch does reach normal, a circuit is closed from battery through the left hand winding of relay 400, contact 425 (10%-l-123L), normal position 430, brush 429 to ground, and the relay 400 by energizing completes a circuit from ground through its Vouter right front contact, upper left contact 417 (12), winding of Vsequence switch magnet 410 to battery. Sequence switch 410 thereupon leaves position 1 2 and moves into its normal position.`

When the sequence switch 410 leaves position 8%., the lower left contact 412'opens and ground .reinovedfromthe conductor 447. The removal of this ground potential permits the deenergization of relay 501, and a circuit is thereby closed from ground through the left back Contact of said relay, upper rightcontact 507 (2}-18), winding of the sender sequence switch magnet 510 to b-attery. The sender sequence switch moves from position 16, through position 18 and into its normal position, 1.

Considering the incoming selector switch it will be remembered that the sequence switch. 110 moves from position 11 into position 12 at the initiation of the restoration of the register sender and the trunk finder and sender selector switches. in position 12 of sequence switch 110, a test is made to determine it' the originating operator in the manual office still has her cord circuit inserted in the jack of the trunk 100, 101. If so the relay 103 will be energized in a inanner similar to that explained in the above mentioned patent to Lundell and Clark No. 1,342,823, issued June 8, 1920. With relay 103 operated, a vcirc-uit is closed from ground through the contact of this relai, upper left contact 105 (124-17), lower contact 107 (8d-17), right hand winding of relay 104 to battery. Relay 104 operates and closes a circuit from ground through the lower contact 108 (Lt-12%), outer front contact of relay 104lowcr left Contact 109 (12), winding of sequence switch 110 to battery, driving said sequence switch out of position 12 and into position 15, which is the talking position.

The sequence switch 210 after leaving position 6 in the manner hereinbefore described, advances to subsequent positions where a test is made of the condition of the called subscribers line in any well-known manner, and upon finding the line idle, said sequence vswitch finally advances to a talking position which is shown in the drawing as position 15. After the incoming selector sequence switch 110 has been advanced out of position 12, `ringing current may be applied to the called subscribers line in any suitable manner. The connection has now been completely established and conversation may take place over the completed talking circuit.

Release of the connection.

' 1 After conversation hasbeen finished and the connection is no longer required, the originating operator in the manual oflice by taking down her cordl circuit permits the deenergization of relay 103, which in turn causes the deenergization of relay 104. A circuit is now closed from battery through the lamp 117, upper contact 108 (3-l-18), outer back contact of relay 104. lower left contact 11,1 (134-18), interruptor 146 to ground. VThe interrupter 146 causes the lamp `117-to flash, signifying -to the operator that the switches may be released. The operator thereupon depresses the key 118, closing a circuit from ground through the contacts of said key, lower right contact 116 (10-1-17), winding of sequence switch magnet 110 to battery.

Sequence switch 110 moves into position 18 where a circuit is closed from battery through the winding of the downdrivc power magnet 123, right contact 115 (18) to ground. The brush shaft 145 is restored to its normal position whereafter a circuit .is completed from battery through the winding of sequence switch magnet 110, upper right contact 116 (6-1-18), segment 135, brush 132 to ground. Sequence switch 110 ioves out of position 18 and into position 1.

When the sequence switch 110 leaves positionl, it opens at its lower right contact 11.? a holding circuit for relay 200. Relay 200 on deenergizing establishes a circuit from ground through its right back contact, lower contact 202 (14+17), winding of sequence switch magnet 210 to battery. Sequence switch 210 of the final selector switch is driven out of position 15 and into position 18. In this position the brush shaft 231 is restored to its normal position by means of a circuit fl'roin battery through the winding of the downdrive power magnet 214, contact 206 (18), to ground. When the brush shaft 231 reaches normal, a circuit is closed -from battery through the winding of sequence switch magnet 210, upper Contact 202 (18), normal position segment 225. brush 222 to ground. Sequence switch 210 leaves position 18 and moves into position 1, and the circuit of the power magnet 214 is severed.

Establish/ment of' a @all mm1/ving translation.

In considering the establishment of the connection just described, a called line number was chosen which did not involve a` tens or units digit greater than four, that. is, one belonging to the second group of five. Accordingly, the register relays which control the final selector switch and its tens and units movements, determine that the number of counting relays to be operated during this movement was something less than five. The next case to be discussed is one wherein the number of the called line contains tens and units digits in the second group of five, or greater than four, and which will consequently involve the operation of the linal switch to make selections in the second five. This means that instead of operating a variable number of counting relays less than five, it will be necessary to operate a variable number of these relays which is greater than five, and therefore greater than the possible number of settings that the registers are capable oi taking. To 

